1. Technical Field
The present invention relates to a noise measurement apparatus and a test apparatus. In particular, the present invention relates to a noise measurement apparatus that measures noise at a location under measurement in a circuit substrate or the like, and to a test apparatus that tests a device under test such as a semiconductor chip.
2. Related Art
One type of testing/analysis of a device under test such as a semiconductor chip involves measuring the noise in the device under test. For example, the noise added to the output of an element under measurement can be measured by bringing a probe pin of a test apparatus into contact with the element under measurement in the device under test, as described in, for example, Japanese Patent Application No. 11-344510. Furthermore, with this method, testing/analysis of the device under test can be performed by measuring a distribution of noise across a plurality of locations under measurement in a semiconductor chip or wafer.
Along with a desire for increased accuracy when testing a semiconductor chip, there is a desire to measure weak noise occurring in the device under test. For example, it is desirable to be able to measure the weak low-frequency noise, such as 1/f noise (flicker noise), occurring due to defects or impurities in the crystalline structure of the semiconductor substrate.
It is difficult, however, to accurately measure weak noise. For example, when measuring noise with the probe pin as described above, noise also occurs in the transmission path of the probe pin. Therefore, the weak low frequency noise occurring at the location under measurement cannot be accurately separated from the transmission path noise and measured.